Articles with reduced tendency to corrode



Patented ct. 6, i936 AR'EKCILES WITH REDUCED TENIDIENCY TQ (CORRQDEHermann Schulz and Carl @arius, Dortmund, Germany, assignors to the firmVereinigte Stahlwerke Alitiengesellschaft, Dusseldorf,

Germany No Drawing. @riginall application May 311, 1933,

Serial No. 673,792. Divided and this application .llune 30, 1936, SerialNo. 88,265. In Germany May 20, 1932 ll (Claim.

The invention relates to articles made from steel and cast iron withreduced tendency to corrode, especially when subjected to the action ofwater, especially sea Water and moist soil and forms a division from ourcopending application Serial No. 673,792, filed May 31, 1933.

The present invention is an improvement of the steel and cast irondescribed and claimed by the applicant in his prior application SerialNo. 450,878, which matured into Patent No. 2,013,600 on Sept. 3, 1935,which is also resistant against sea water and moist soil. The priorprocess is based upon special electrolytic actions which are therebycaused, that the steel or cast iron is alloyed with copper, antimony,arsenic or tin and incombination with one or several of these additionswith magnesium, nickel or aluminum. Said elements are used in .the priorprocess in the following amounts: antimony, arsenic, tin in amountsbetween 0.05 and 5%, singly or together, copper .in amounts up to 1%,magnesium between 0.1 and 5%, aluminum between 0.05 and 5%.

Further researches have shown that the titanium and vanadium elementsact in a similar way as the magnesium and aluminum elements usedsecondly according to the main patent, and

they are not only equivalent to these elements, especially aluminum, buteven superior thereto. Since this has been found out, it is possible toreplace the aluminum as well as magnesium partly by titanium orvanadium. The favourable influence of these two elements could not beforeseen either on account of their electrochemical or chemicalbehaviour.

A further economically advantageously acting influence of titanium andvanadium, owing to which steels alloyed with these-elements will excelcompared with aluminum containing steels, is

' that the capacity of steels alloyed with titanium and vanadium ofoffering increased resistance to the attacks of water will findexpression already a short time after the beginning of corrosion in aconsiderable reduction of corroding speed. For example the corrodingspeed in sea water will be reduced already after 14 days approximately20% and in river water about 40% compared with that of copper-nickelsteels alloyed with aluminum. Steels according to the invention arefurther distinguished by a perfectly uniform rusting of their surfaceexposed to the corroding agent. Local corrosion attacks in the form ofdents or holes or notch-like depressions, which cause a reduction of themechanical qualities of a steel, do not happen. From the point of viewunlimited. However, it is advisable when adding titanium not to exceed1% and in case of vanadium 0.5%, as a greater addition would not aiiordany extra advantages.

Thus the invention comprises articles with a reduced tendency to corrodeunder the action of a corroding agent, more particularly the moisturecontained in water, seawater and moist soil; said articles being madefrom a ferrometal alloy containing 0,2-l% copper, titanium between about0.1 and 1%, vanadium between about 0.1 and 5% and in addition magnesiumin amounts between about 0.1 and 5% and the balance substantially alliron, the alloying elements copper, and magnesium forming together withtitanium and vanadium a firmly adhering skin on the articles, due to thecorroding attack by said corroding agent.

It may be mentioned that the further composition of the alloys besidesthe elements above specified is the usual one. Thus the alloy may bealloyed for some other reasons with the usual amounts of elements suchas for example manganese, silicon, phosphorus, chromium, tungsten,molybdenum, cobalt, boron, zirconium, beryllium, as has been stated inmy prior patent and in the case of steels the accompanying elements maybe present in approximately the following amounts:

We claim:

Articles with a reduced tendency to corrode under the action of acorroding agent, more particularly the moisture contained in water,sea,- water and moist soil; said articles being made from a ferrometalalloy containing 0.2 1% cop per, titanium between about 0.1 and 1%,vanadium between about 0.1 and 0.5% and in addition magnesium in amountsbetween about 0.1 and 5% and the balance substantially all iron, thealloying elements copper and magnesium forming together with titaniumand vanadium a firmly adhering skin on the articles, due to thecorrocling attack by said corroding agent.

HERMANN SCHULZ.

CARL CARIUS.

